| 배향된 $beta-Si_3N_4$ Whisker를 함유하는 $Si_3N_4$ 복합체의 기계적 특성에 미치는 소결조제와 소결온도의 영향 |
| 김창원, 최명제, 박찬, 박동수1 |
부경대학교 재료공학부
1한국기계연구원 요업재료그룹 |
| Effect of Sintering Additives and Sintering Temperature on Mechanical Properties of the $Si_3N_4$ Composites Containing Aligned $beta-Si_3N_4$ Whisker |
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| ABSTRACT |
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Gas pressure sintered silicon nitride based composites with 5 wt% $beta$-Si3N4 whiskers were prepared, and the variations depending on sintering additives and sintering temperature were studied. Sintering additives were 6 wt% Y2O3-1 wt% MgO(6Y1M), 6 wt%Y2O3-1 wt% Al2O3(6Y1A), 6 wt% Y2O3-1 wt% SiO2(6Y1S), and whiskers were unidirectionally oriented by a modified tape casting technique. Samples were fully densified by gas pressure sintering at 2148 K and 2273 K. As the sintering temperature increased, the size of large elongated grains was increased. Three point flexural strength of 6Y1M and 6Y1M samples was higher than that of 6Y1S sample, and the strength decreased as the sintering temperature increased. The indentation crack length became shorter for the sample sintered at higher temperature, and the difference between the cracks length parallel to and normal to the direction of whisker alignment was decreased. In case of cracks 45$^{circ}$off the whisker alignment direction, the crack length anisotropy disappeared. |
| Key words:
Sintering additives, Sintering temperature, Tape casting |
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